A. Field of the Invention
This invention relates to water closets in which the water storage tank has a restricted top opening. Specifically, it resides in an insulating liner which is specially designed for use with such tanks.
B. Description of the Art
Sweating of water closet tanks on hot and humid days has long been a source of annoyance, and a cause of damage to bathroom floors. For this reason, drip trays attached to the bottom of the flush tank were developed to catch condensation. However, these trays were found to be objectionable because of the sanitary and odor problems which resulted when the condensation stood in the tray for extended periods of time.
Another attempt to solve the condensation problem involved the application of an absorbent fabric to the exterior surface of the tank. This covering was intended to soak up any condensation which formed on the tank, and then to let moisture evaporate slowly during less humid periods. However, this approach was unsatisfactory because the fabric could easily become saturated, and because damp fabrics can suffer severe odor problems.
The art then turned to the use of insulating liners which fit inside the toilet tank. These liners formed an insulating barrier between the cold storage water and the outside tank wall, and thus the formation of condensation on the exterior of the toilet tank walls was inhibited. One type of prior art liner, a preformed rectangular rigid plastic liner, could be slid into the top opening of a rectangular tank. Another type of liner, another form of rigid plastic liner, could be formed in place by various casting methods.
While such liners were acceptable for conventional rectangular tank designs, highly ornamental water closets were developed that had tanks that were "low profile" and generally trapezoidal in shape. When conventional rectangular preformed liners are placed into these low profile, trapezoidal shaped tanks, there is often too much waste of water storage space along the sides of the tank. This volume loss is critical due to the additional loss from narrowing of the tank near its top. (The less storage water available, the harder it is to completely clean the bowl with one flush.)
If one chooses to make a prior art rigid preformed liner conform to the design of a trapezoidal tank (so as to maximize water storage space), one would not be able to get the rigid liner through the "restricted" top opening. Moreover, if one tries to mold a liner in place which conforms to the inwardly sloping tank walls, conventional molding techniques become very difficult and expensive (e.g. getting a one-piece core out of a negative mold).
Thus, it can be seen that the need has existed for an improved means of preventing water condensation on the exterior of a low profile, trapezoidal shaped toilet tank.